WASHINGTON — The U.S. Senate voted narrowly Friday to advance the nomination of Brett Kavanaugh, President Donald Trump’s choice for the Supreme Court.

But the preliminary step does not guarantee he has enough support for final confirmation this weekend.

The tally was 51 to 49. Sen. Lisa Murkowski (R-Alaska) voted against moving forward, a sign she will not support Kavanaugh in the final vote. She is the first Republican to break with the party and joining most Democrats in opposing Kavanaugh.

But the nomination advanced thanks largely to Sen. Joe Manchin (D- W-V.), who joined Republicans to vote yes.

Sen. Susan Collins (R-Maine), a key undecided Republican, voted to advance the nomination but said she would announce her final decision Friday afternoon.

Votes on Friday’s motion to end debate on the nomination do not necessarily reflect how senators will vote Saturday, when a final vote is expected. Sometimes voting to end debate is done by senators as a courtesy to permit a final vote to take place.

The timing of the final vote is also up in the air. A hitch arose Thursday when Sen. Steve Daines (R-Mont.), who supports Kavanaugh, said he would not be in D.C. on Saturday because his daughter is getting married in his home state.

If the count on Kavanaugh ends up being tight, that might force GOP leaders to keep the voting open for longer than expected, perhaps until late Saturday or Sunday.

Kavanaugh’s confirmation process was scrambled by allegations of sexual misconduct and assault that emerged in recent weeks. Christine Blasey Ford, a Palo Alto University professor, said he tried to rape her in high school, and Deborah Ramirez said he exposed himself to her when they were college classmates.

The White House ordered a supplemental FBI background check after a handful of Republicans threatened to withhold their support from Kavanaugh, and senators began reviewing the confidential report on Thursday.

On Friday morning, Sen. Charles Grassley (R-Iowa), chair of the Senate Judiciary Committee, repeated his contention that the investigation did not find any evidence for the allegations. He said Democrats’ treatment of Kavanaugh has been “nothing short of monstrous.”

“Before left-wing outside groups and Democratic leaders had him in their sights, Judge Kavanaugh possessed an impeccable reputation and was held in high esteem by the bench and the bar alike,” Grassley said.

Sen. Dianne Feinstein (D-Calif.), the Judiciary Committee’s ranking Democrat, said she was disturbed by the allegations and Kavanaugh’s subsequent appearance during an emotionally charged hearing last week. Kavanaugh, who currently sits on the D.C. Circuit Court of Appeals and previously worked for the independent counsel’s office during the investigation of President Bill Clinton, described opposition to his nomination as “revenge on behalf of the Clintons.”

“We saw a man filled with anger and aggression,” Feinstein said. She added, “This behavior revealed a hostility and a belligerence that is unbecoming someone seeking to be elevated to the United States Supreme Court.”

In an essay published Thursday by the Wall Street Journal, Kavanaugh said he regretted parts of his opening statement and testimony, saying they reflected his frustration.

President Trump used the fight over Kavanaugh’s nomination to rile up his supporters at a rally in Rochester, Minn., on Thursday night, drawing chants of “we want Kavanaugh” from the crowd.

“All you have to do is look at the polls over the last three or four days and it shows that their rage-fueled resistance is starting to backfire at a level that no one has ever seen before,” he said.

Although some polls have shown increasing Republican enthusiasm ahead of the November midterm elections that will determine control of Congress, Kavanaugh’s support among voters as a whole is historically low.